Yamaha rider Lorenzo, the reigning world champion, was third, 5.704sec behind the winner.

Marquez began his first MotoGP campaign last April with a third-place finish in the season-opener at Qatar.

At the Circuit of the Americans race in Austin, Texas, later that month, he became the youngest rider in series history to win a pole and a race.

He failed to reach the podium only once this year, after a crash at a race in Mugello in June.

With his win Sunday he completed a sweep of the season's three US races. He also won at Laguna Seca last month.

"I didn't make such a good start," said Marquez, who was notching his third straight win and fourth of the season. He also won in Germany.

"But I knew before the race that the most important part was toward the end of the race. I just tried to follow Dani and Jorge. Then I tried to attack. Now we go back to Europe, and we would like to continue."